1. Field of the Invention
The present invention relates generally to vortex generators which assist in the flow of fluids over lifting surfaces such as wings or wing flaps, and to lifting surfaces having such vortex generators, and more particularly, but not by way of limitation, to concealable vortex generators which are attached to flap actuators of lifting surfaces or which are revealed by the movement of flaps or slats attached to such lifting surfaces for assisting in the motion of fluids over lifting surfaces such as wings, elevators, rudders and ailerons of aircraft, rudders of ships and lifting surfaces of racing cars, and to lifting surfaces which have such concealable vortex generators.
2. Discussion of the Prior Art
Vortex generators (VG's) are vane-like structures which are attached to aircraft wings, or other lifting surfaces or fuselages. The applicant admits that vortex generators which are attached to surfaces wherein they are permanently exposed are old in the art. However, the applicant is not aware of any vortex generators attached to lifting surfaces which are alternately concealable and exposable.
Vortex generators ar often added to aircraft during the test-flight phase of an aircraft development to enhance a wing design or to fix an unforeseen problem with the flow of air over the wing surface. These problems may include loss of lifting effectiveness, increased buffet, a loss in lift-to-drag ratio, or a reduction in stability.
Many of these difficulties can be attributed to flow separation (separation of the flow from the wing or lifting surfaces) and it has been demonstrated that VG's can be an effective mechanism for delaying the onset of these difficulties. Vortex generators on aircraft are used to mix high-energy air outside of the boundary layer with the retarded air within the boundary layer. This allows the boundary layer to remain attached longer in regions of the flow with adverse pressure gradients.
Deflection of leading-edge and trailing-edge flaps has a large impact on the pressure gradients on aircraft. The present invention comprises a novel use of vortex generators to assist the flow in traversing through adverse pressure gradients generated by flap deflections. The present invention, when applied to aircraft, can enhance the performance of fighter, commercial or general aviation aircraft.
Vortex generators were first used in the late 1940s to increase wind-tunnel diffuser efficiencies. Following their initial use, a number of experimental studies indicated that if VG's were incorporated properly, they could be used to improve lifting effectiveness, extend the point of buffet onset, improve lift-to-drag ratio, or enhance stability. These benefits are achieved by delaying separation. The vorticity that is shed by the VG mixes the high-energy air external to the boundary layer with the retarded air within the layer.